When I used to sell tickets on the railway, I noticed that the ticketing programme had underlined letters, so I tried doing alt + those letters and it worked. I spent an evening shift at a remote outstation getting to grips with the shortcuts, then when it came to doing the morning rush at a busier station, it was talk of the town.

I worked at a call centre for a shopping channel years ago, at a time when they were trying to get everyone to ditch this DOS-based ordering programme where you mainly use the F keys for operations in favour of this user-friendly GUI where you could do everything with the mouse, and would you believe, people were routinely faster with the keyboard. I suppose it hadn't occurred to them that anyone can get used to doing keyboard controls if they're sat at a computer eight hours a day.